Method of manufacturing artificial silk and other products from nitrocellulose



Patented May 11, 1926.-

UNITED STATES PATENT OFFICE.

EMILE BINDSCHEDLER, F LANsnowNn,

PENNSYLVANIA, AND GEORGE J'UER, 0F

HOIEWELL, VIRGINIA, ASSIG-NORS TO TUBIZE ARTIFICIAL SILK COMPANY OFAMERICA, A CORPORATION OF DELAWARE. v

No Drawing.

Our invention relates to the known process in which the collodionobtained by dissolvin nitrocellulose hydrate in a mixture of ethyalcohol and ether is given desired form .by exuding it through anorifice and the filament or other product thus formed is coagulated bythe removal of the solvents.

It has been proposed to coagulate nitrocellulose collodion by passing itinto a bath of dilute ethyl alcohol, preferably of a strength varyingfrom 25 to 60%. We have found that to secure clear and lustrousfilaments,

'the coagulating bath should have a strength of at least 40%. We havealso discovered that the rate of coagulation in such a bath can beregulated by dissolving in dilute ethyl alcohol a neutral inorganic saltorsalts.

Such regulation of coagulation can be availed of to vary in some degreethe character of the product and the operation of the process. 1

Certain metallic salts, especially haloids, when dissolved in dilutealcohol have in most cases a pronounced retarding effect on the rate ofcoagulation. We found calcium chloride and magnesium chloride especiallywell adapted for the purpose, these salts, havin a further advantage ofbeing cheap and t eir aqueous solutions are miscible,

to a great extent, with the usual ether-alcohol mixture.

lVhere acceleration of coagulation is desired, zinc chloride ispreferably used because among other reasons, it has the valuable proerty of being soluble not only in alcohol, ut also in ether.

We have availedourselves of the retarding effect of calcium chloride orsimilar saltdissolved in dilute alcohol on the coagulation of the exudedfilaments to produce a thread of finer denier and we effect this bywinding up the filaments at a speed greater than the rate of exudationof the collodion through an orifice, the resultbe-ing that the stillpiestic thread is drawn out and made finer before.

coagulation gives permanent form to it.

By preference we complete thecoagulation and extract the salt by passingthe'thread through a second bath of dilute ethyl alcohol of from 40 tostrength, but this is not essential and the thread may be passeddirectly to the bobin rotating in water which will remove any remainingsolt elit, alcohol Application filed July 1, 1924. Serial No. 723,485.

METHOD OF MANUFACTURING ARTIFICIAL SILK AND OTHER PRODUCTS FROM NITROOELLULOSE. Y v

andsalt. The solvents and salt solutions can be easily and almostcompletely recovered agu'ation bath consisting of 50% ethyl alcohol inwhich 20 parts calcium chloride have been dissolved per 100 volumeparts. The threads coming out of the orifices in a semi-coagulated stateare elongated by tension'to the desired fineness and the filaments arewashed preferably first with 40% alcohol andfinally with water.

After twisting and reeling, the threads are denitrated in the usualmanner and clear and lustrous filaments are produced.

The following is a specific example of the application of our inventionin case acceleration of the coagulation is desired:

Nitrocellulose hydrate containing 20 to 30% water is dissolved in amixture of 50 parts ether and 50 parts ethyl alcohol and the collodionso formed, is spun into ethyl alcohol of 40% strength in which 50 partsof zincchloride have been dissolved per 100 volume parts of dilutealcohol, the threads so formed are directly wound on bobbins, rotatingin water.

- Having now'described-our invention, What we claim as new and desire tosecure by Letters Patent, is: f

1. In the .process manufacturing formed. products from nitrocellulosehydrate dissolved in alcohol and ether unadmixed :with other chemicalsby exuding the collodion'through an orifice to give form to the productand coagulating the exuded product, the method of regulating coagulationwhich consists in'ex'uding the collodion into a bath composed of one ormore neutral inorganic salts dissolved in dilute alcohol.

- 2. In the process of manufacturing formed products from nitrocellulosehydrate dissolved in alcohol and ether by exuding the collodion throughan orifice to give form to the product and coagulating the exudedproduct, the method of regulating coagulation which consists in exudingthe collodion into a bath composed of one or more metallic haloidsdissolved in dilute alcohol.

3. In the process of manufacturing formed products from nitrocellulosehydrate dissolved in alcohol and ether by exuding the collodion throughan orifice to give form to the product and coagulating the exudedproduct, the method of retarding coagulation which consists in exudingthe collodion into a bath composed of calcium chloride dissolved indilute alcohol.

4. .In the method of manufacturing artificial silk from nitrocellulosehydrate dissolved in alcohol and ether unadmixed with other chemicals byexuding the collodion through an orifice, and coagulating the filament,the method of retarding the coagulation and producing a filament of finedenier which consists in exuding the collodion filament into a bath ofdilute alcohol having dissolved in it neutral inorganic salts whichretard coagulation and drawing the filament through said bath at a rateexceeding the rate of exudation so as to elongate and reduce the denierof the filament.

5. In the process of manufacturing formed products from nitrocellulosehydrate dissolved in alcohol and ether unadmixed with other chemicals byexudin the collodion through an orifice to give Iorm to the product andcoagulating the exuded product, the method of regulating coagulationwhich consists in exuding the collodion into a bath composed of one ormore neutral inorganic salts dissolved in dilute alcohol of from 40 to60 strength.

6. In the process of manufacturing formed products from nitrocellulosehydrate dissolved in alcohol and ether unadmixed with other chemicals byexuding the collodion through an orifice to give form to the product andcoagulating the exuded prodnot, the method of regulating coagulation.

which consists in exuding the collodion into a bath composed of one ormore neutral in organic salts dissolved in dilute alcohol and afterwardsthrough a second bath of alcohol diluted to 40 to 60 strength.

EMILE .BINDSCHEDLER. GEORGE JUER.

